WO2013108421A1

WO2013108421A1 - Solder alloy for acoustic device

Info

Publication number: WO2013108421A1
Application number: PCT/JP2012/062009
Authority: WO
Inventors: 赤木　一平; 秀樹時本; 聖記鈴木; 雅文清野; 勇大澤; 上島　稔
Original assignee: 千住金属工業株式会社
Priority date: 2012-05-10
Filing date: 2012-05-10
Publication date: 2013-07-25
Also published as: US20140186208A1; MX2013009113A; AU2012363597B2; EP2644313B1; EP2644313A4; KR101305801B1; TWI441926B; TW201402831A; JPWO2013108421A1; EP2644313A1; CN103402694B; CN103402694A; JP5186063B1; AU2012363597A1

Abstract

　Disclosed is a solder alloy for an acoustic device, which used as solder for bonding various electronic components in an electronic circuit such as a filter circuit NW for an audio system, and which is composed of six elements (Sn, Ag, Cu, Sb, In, Ni, Pb) in an appropriate quantity in order to obtain a high sound quality and a high audio value. One example of preferable contents is: 1,0 to 1,01 mass % of Ag, 0,71 to 0,72 mass % of Cu, 0,003 to 0,0037 mass % of In, 0,016 to 0,017 mass % of Ni and 0,0025 to 0,0035 mass % of Pb, with the remainder consisting of Sn.

Description

Acoustic solder alloy

The present invention relates to an acoustic solder alloy that can be applied to a joining solder for connecting an electronic component to a printed circuit board used in an audio system or the like.

In order to improve sound quality in a sound reproduction device (sound product) as an audio system, not only the electronic components used in the sound reproduction device are selected, but also a circuit of a printed circuit board used in an amplifier constituting the device. It is necessary to comprehensively consider the design, the placement of components on the printed circuit board, the materials used as the connection line between the final amplifier (output amplifier) and the speaker (OFC (Oxygen Free Copper, etc.)).

Of these, the selection of electronic components and circuit design when using printed circuit boards are already being implemented as sound quality improvement measures. However, in order to further improve sound quality and obtain a sound reproduction device with high auditory evaluation, Solder for joining parts is attracting attention.

(Patent Document 1) to (Patent Document 3) are known as solders for joining electronic components.

JP-A-11-277290 JP2002-239780 Japanese Patent Laid-Open No. 2003-230980 is related to a quaternary solder alloy in which Ni is added to (Sn / Ag / Cu), and has improved thermal shock resistance. Patent Document 2 is a solder alloy pursuing bonding reliability and the like, and Patent Document 3 is an invention related to a solder alloy with improved bonding reliability.

By the way, the above-mentioned Patent Documents 1 to 3 do not mention that the alloy composition and content of solder for joining electronic components affect the sound quality and audibility evaluation.

It was confirmed by the present applicant through various experiments that the sound quality and the audibility change by changing the metal composition and content of the solder alloy. That is, it has been found that the combination of the alloy composition of the solder for joining electronic parts and the content thereof are one of the important factors for improving the sound quality and obtaining a high audibility evaluation.

Therefore, the present invention solves such a conventional problem, and provides an acoustic solder alloy that can be applied to an audio system or the like that can improve sound quality and obtain high audibility evaluation.

In order to solve the above-described problems, the acoustic solder alloy according to the present invention has an Ag of 0.8 to 1.20 mass%, Cu of 0.65 to 0.75 mass%, and In of 0.002 to 0.00. 004% by mass, Ni is 0.01 to 0.02% by mass, Pb is 0.005% by mass or less, and the balance is Sn. By selecting such a composition element and its content, an acoustic solder alloy with high sound quality and high audition evaluation value can be obtained.

According to the present invention, a ternary solder alloy is mainly composed of (tin Sn / silver Ag / copper Cu), and a small amount of indium In, nickel Ni and lead Pb is added thereto, and each content is appropriately set. By setting the value, it is possible to realize a high-quality sound characteristic and a high-quality audio solder alloy for auditioning.

It is a block diagram which shows an example of the audition evaluation apparatus with which it uses for description of this invention. It is a circuit diagram of the low-pass filter circuit which shows an example of the filter circuit used for the audition evaluation apparatus of FIG. FIG. 3 is a component layout diagram of a low-pass filter circuit on a printed board. It is a circuit diagram of the high-pass filter circuit which shows an example of the filter circuit used for the audition evaluation apparatus of FIG. FIG. 3 is a component layout diagram of a high-pass filter circuit on a printed board.

Next, an example of the acoustic solder alloy according to the present invention will be described in detail with reference to the drawings and the like when applied to the solder for joining electronic components used in the circuit system constituting the audio system described above.

As a solder for joining that may affect the sound quality and the audition evaluation, an acoustic solder alloy was prepared for the audition evaluation.
(1) Auditory solder alloy for soldering As the solder for joining electronic parts, the most common ternary solder alloy (tin Sn / silver Ag / copper Cu) used as a joining solder for electronic parts is used. Solder alloy) is used as the base.

As the audition experiment confirmed that the trial evaluation was changed by adding a few metals to the ternary solder alloy, it was confirmed that the various metal audits were repeated. Chose as.
(Added metal)
"Indium In, Nickel Ni, Antimony Sb, Bismuth Bi, Iron Fe, Arsenic As and Lead Pb"
Since lead Pb is a trace element contained in tin Sn composing the ternary solder alloy, the trace amount described above is actually added to the quaternary solder alloy obtained by adding lead Pb to (tin Sn / silver Ag / copper Cu). Auditory evaluation was performed as a 6-element solder alloy to which metal was added.

(2) Number of prepared solder solder alloys for jointing As an additive metal, select two types of metals in addition to lead Pb, and adjust the amount of each additive and the amount of other quaternary metals, An acoustic solder alloy was prepared. Actually, nine kinds of acoustic solder alloys having the same metal composition and different addition amounts were prepared for listening.

(3) Audition device (audition evaluation device)
FIG. 1 shows an example of a trial listening evaluation apparatus 10. As an electronic circuit for trial listening evaluation, a filter circuit NW in which an electronic circuit is configured by soldering discrete components onto a printed circuit board (circuit board) is exemplified.

Since the sound source is usually recorded in stereo, the playback device is composed of a pair of left and right speakers. For convenience, only one side will be described.

When a CD (compact disc) is used as a sound source, the sound source is reproduced by a sound source reproducing apparatus having a rotation system such as a CD player and listened to the sample. Unevenness, eccentricity, and the like may occur, and the location affected by each trial listening may be different, which hinders proper evaluation of the listening. Therefore, this time, when reproducing a sound source for trial listening, a sound source reproducing apparatus with a rotating system such as a CD player is not directly used. In other words, when a CD is used as a sound source, the sound source can be reproduced under the same conditions by reproducing the CD with a CD player and using the recording once in a semiconductor memory such as a USB memory as the sound source. did.

The audio signal from the sound source 20 is supplied to the filter circuit NW via the output amplifier 30, and in this example, it is divided into two ways of the mid-low range and the high range. Therefore, the filter circuit NW (NW0) includes a low-pass filter (LPF) 40 and a high-pass filter (HPF) 50, both of which are configured using a printed circuit board (circuit board).

The output signal from the low-pass filter 40 is supplied to the speaker (woofer) WF for the mid-low range through the connection lines La and Lb. Similarly, the output signal from the high-pass filter 50 is supplied to the loudspeaker (tweeter) TW via the connection lines Lc and Ld.

FIG. 2 shows an example of the low-pass filter 40, which is composed of a parallel circuit composed of an iron core coil 43 and a capacitor 44. In this example, a coil having a wire diameter of 1.2 mmφ is used as the iron core coil 43. The inductance value used was 0.45 mH. A capacitor 44 having a withstand voltage of 250 V (DC) and 12 μF was used.

In actuality, the low-pass filter 40 uses a printed circuit board 46 as shown in FIG. 3, and an iron core coil 43 and a capacitor 44 are disposed on one surface thereof with a positional relationship as illustrated. Screw

type terminal blocks

47 and 48 each having two input terminals (40A and 40A) and output terminals (42A and 42A) are provided on both left and right ends of the printed circuit board 46, respectively.

As a result, the connection between the output amplifier 30 and the low-pass filter 40 is not soldered, but is a screw type (insertion type), and between the low-pass filter 40 and the connection lines La and Lb connected to the speaker WF, It is mechanically connected not by solder but by a screw type.

As a result, the low-pass filter 40 shown in FIG. 2 is configured such that the iron core coil 43 and the capacitor 44 (both electronic components) are soldered onto the printed circuit board 46 by solder (acoustic solder alloy), as indicated by the black circles in FIG. It is constructed by joining four places. The number of junctions was counted including the connection with lead wires for electronic components. Actually, since the two input terminal portions and the two output terminal portions are respectively soldered to the printed circuit board (circuit board), a total of eight positions are joined in this example.

The reason why the screw-type (insertion-type)

terminal blocks

47 and 48 are used as the terminals is to allow easy exchange of a plurality of filter circuits NW, which will be described later, for comparing the audition.

FIG. 4 shows an example of the high-pass filter 50, which is composed of a parallel circuit composed of a capacitor 53 and an iron core coil 54. The capacitor 53 having a withstand voltage of 250V (DC) and 6.8 μF is used. In this example, a coil having a wire diameter of 1.0 mmφ is used as the coil 54. The inductance value used was 0.4 mH.

The terminal 52A and the high frequency reproduction speaker TW are connected by connection lines Lc and Ld. A pair of attenuating

resistors

56 and 58 are connected in series between the terminal 52A side and the terminal 56a, and the terminal 56b is derived from the midpoint of connection. The

terminals

56a and 56b are used for attenuating the output signal as necessary.

In actuality, the high-pass filter 50 also uses a printed circuit board 66 as shown in FIG. 4, and a capacitor 53 and an iron core coil 54 are arranged on one surface thereof with the positional relationship shown in the figure. In addition, screw type terminal blocks 67 and 68 each having two input terminals (50A, 50A) and four output terminals (52A, 52A, 56a, 56b) are provided. As a result, the connection between the output amplifier 30 and the high-pass filter 50 is not a solder, but a screw type (plug-in type), and the high-pass filter 50 and the speaker TW are mechanically connected by a screw type instead of solder. It is connected to the lines Lc and Ld.

As a result, the high-pass filter 50 shown in FIG. 4 includes a capacitor 53 and an iron core coil 54 (both electronic components) that are totalized by solder (acoustic solder alloy) on the printed circuit board 66, as indicated by black circles in FIG. Four places are joined together. Actually, since the two input terminal portions and the two output terminal portions are respectively soldered to the printed circuit board (circuit board), a total of eight positions are joined in this example.

As described above, the reason why the screw type (plug-in type) terminal blocks 67 and 68 are used as the terminals is to make it easy to exchange with a plurality of filter circuits NW described later for the trial comparison. .

(4) Specification of acoustic solder alloy used for audition listening As described above, the acoustic solder alloy for audition evaluation used in addition to the base (Sn / Ag / Cu) metal (metal element) In addition, there is a trace amount of Pb, and any two of In, Ni, Sb, Bi, Fe and As are added as a trace amount of added metal.

In order to improve the audition evaluation accuracy and find a better acoustic solder alloy, the following example is based on the above-mentioned 10 kinds of metals (Sn, Ag, Cu, Pb, In, Ni, Sb, Bi, Fe, As). Among them, based on four kinds of metal elements (Sn, Ag, Cu, Pb), and by further extracting two kinds of metals from the remaining metals (six kinds), six kinds of metals A set of acoustic solder alloys (6-element solder alloys) is formed.

And, even in the same composition metal, the content (addition amount) is changed, and in this example, nine kinds of acoustic solder alloys are prepared as one set, and this is used as a joining solder for audition evaluation.

Further, a total of 15 kinds of acoustic solder alloys with different combinations of composition metals to be extracted were prepared, and audition evaluation was performed using a filter circuit NW using the acoustic solder alloys as bonding solder.

Therefore, as shown in FIG. 1, as the trial listening evaluation apparatus 10, 15 types of filter circuits NW0 to NW15 are used. Other circuits and speakers are the same. The combinations of the filter circuits NW0 to NW15 and the extracted elements are as shown in (Table 1).
Common metal elements (Sn / Ag / Cu / Pb) used as acoustic solder alloys are listed in the column.

(5) The best acoustic solder alloy As a result of the audition evaluation, a small amount of lead Pb, indium In, and nickel Ni are added to (tin Sn / silver Ag / copper Cu), and the addition amount is appropriately selected. The 6-element solder alloy (Sn / Ag / Cu / In / Ni / Pb) obtained the highest audition evaluation value (maximum value was 5.0).

As a specific example will be described later, it is necessary to verify whether or not the highest audition evaluation by the listener is an appropriate audition evaluation.

The high auditory evaluation achieved by improving the sound quality is a listener's evaluation to the last, so even if the evaluator is an audio expert, the evaluation (listening evaluation value) varies. As one means (quantitative means) for verifying whether or not there is little variation in evaluation, first, a popular sound source often used for evaluation of sample listening was used as a sample, and items for sample evaluation were set. Next, the audition evaluation was analyzed by a multiple regression model using the correlation between the audition evaluation value and the predicted value (estimated value or theoretical value).

(6) Samples of sound sources and evaluation items for trial listening The following three music (popular, classical music and vocals) were referred to as popular sound sources that are often used for trial listening evaluation. The sound source 20 used was a CD that was reproduced and stored once.
(I) vincent
(Ii) Carmen Valley (iii) somewhere somebody
An example of the trial listening evaluation items is shown in (Table 2). In this example, a trial listening evaluation was performed on a total of 10 items from a bass characteristic to a musical instrument characteristic with a maximum score of 5 points, and the average value was used as a trial listening evaluation value.

(7) Analysis of the audition evaluation As described above, the analysis of the audition evaluation is a set of extracted six-component alloy alloys and multiple regressions for each of nine types of acoustic solder alloys having different contents. Analyze and do the same for 15 acoustic solder alloys with different compositional metals. The one with the highest multiple correlation in this multiple regression analysis was the acoustic solder alloy (invention) with the highest audition evaluation.

In the following example, multiple regression analysis provided by Excel (registered trademark) was used as an analysis tool. In this example, multiple regressions derived by multiple regression analysis with the main component (Sn / Ag / Cu) and the plural (and therefore three) metal elements added to this as explanatory variables (independent variables), respectively. Check how much the expression (multiple regression model) reflects the audition evaluation value (the dependent variable (objective variable) that is the actual measurement value, the maximum value is 5.0) while changing the explanatory variables. did.

(8) Relationship between the grouping of acoustic solder alloys and the correspondence table of multiple regression analysis In conducting multiple regression analysis, the acoustic solder alloys are grouped as shown in (Table 1).

(1) Group 1 acoustic solder alloy The composition of acoustic solder alloy of this group is
"Group 1 acoustic solder alloys: (Sn, Ag, Cu, In, Ni, Pb)"
It is.

Correspondence tables showing the results of the multiple regression analysis when using this acoustic solder alloy are shown as (Table 3 to Table 5) and (Table 6 to Table 8) in the combination examples of (Table 1). Tables 3 to 5 show the results of multiple regression analysis of the acoustic solder alloys according to the present invention.
Note that the solder alloy shown in data 7 is a typical solder alloy as a lead-free solder composed substantially of (Sn · 3Ag · 0.5Cu). Therefore, the evaluation was performed based on this solder alloy.

In (Table 3), “present example 1” and “present example 2” indicate the composition elements and contents (mass% (Wt%)) of the acoustic solder alloy according to the present invention. The trial listening evaluation value is a dependent variable, that is, an actual measurement value, and the explanatory variable is each content (addition amount) of Ag, Cu, In, Ni, and Pb. The results of the multiple regression analysis of the solder alloy for sound comprising these contents are as shown in (Table 4) and (Table 5).

From (Table 3) and (Table 5), the multiple regression equation in this case is as follows. Let the predicted value be y.

y = 0.1104879Ag + 0.072135Cu
+ 376.93035In + 4.651292Ni
-45.72814Pb + 3.6386376
(1)
Here, since the multiple regression coefficient of Pb is negative, it can be said that the addition amount of Pb is preferably as small as possible. Since Pb is also contained in the high-purity Sn component, a small amount of In or Ni is added in order to minimize the influence of this Pb.

As shown in (Table 4), since the multiple correlation coefficient R between the value y predicted by the multiple regression equation and the actual trial listening evaluation value Y is “0.9814333”, it is very close to “1.0”. It can be seen that there is a very strong correlation between the two.

Since the multiple determination R2 (determination coefficient R2) is “0.9632113” and the correction R2 (degree of freedom corrected determination coefficient R2) is also “0.9018968”, the application rate (applicability accuracy) of the multiple regression equation y is It turns out to be very good.

Furthermore, in the analysis of variance table in (Table 5), since the significant F is “0.023169799”, there is a correlation with a probability of 97.7% (= 100% −2.3%). It can be said that the reliability of the multiple regression equation y calculated from the multiple regression coefficients of (Table 3) and (Table 5) is very high.

Therefore, it can be said that the test evaluation value Y “5.0” (maximum evaluation value) in the acoustic solder alloys of “this example 1” and “this example 2” shown in (Table 3) is a very reliable evaluation value. As described above, the combination of the composition elements and the content (addition amount) of the acoustic solder alloy shown in “this example 1”, “this example 2”, etc. have high sound quality and the highest audition evaluation value can be obtained. It turns out that it is suitable as a joining solder.

(Table 3) exemplifies acoustic solder alloys in the ranges shown in “Example 1” and “Example 2” as preferable examples of appropriate acoustic solder alloys.

The content of the acoustic solder alloy is (Sn · Ag (1.0 to 1.01% by mass) · Cu (0.71 to 0.72% by mass) · In (0.003 to 0.0037% by mass). ) · Ni (0.016 to 0.017% by mass) · Pb (0.0025 to 0.0035% by mass)).

The content of the acoustic solder alloy in the present invention is not limited to these ranges, and can be expanded to the following ranges.

(Range of content of acoustic solder alloy in this invention)
“Sn (remainder), Ag (0.8 to 1.20), Cu (0.65 to 0.75), In (0.002 to 0.004), Ni (0.01 to 0.02), Pb (≦ 0.005) ”
On the other hand, the trial listening evaluation values in data 1 to data 7 shown as comparative examples are as shown in (Table 3). Tables 4 and 5 show the results of multiple regression analysis when listening with the same compositional elements while changing the content.

In Table 3, when the contents are as shown in Data 1 to Data 7, even in the case of an acoustic solder alloy using the same composition metal, the maximum audition evaluation value is “4.35”. Thus, it can be seen that the acoustic solder alloy is inferior to “this example 1” and “this example 2”.
(Table 6) to (Table 8) belonging to Group 1 show acoustic solder alloys made of the same composition elements, and the contents are changed.

Data 1 to 6 in (Table 6) are exactly the same as data 1 to 6 in (Table 3), but data 8 to 10 in (Table 6) are newly added data. Since data 7 in (Table 3) is a solder based on the standard as described above, it was excluded from the evaluation in (Table 6).
(Table 6) shows the audition evaluation value Y (dependent variable as an actual measurement value) and explanatory variable values from Data 1 to Data 6 and Data 8 to 10, and (Table 7) and (Table 8) are weights. The regression analysis result is shown.

Even though the detailed explanation is omitted, it can be seen from the results of the multiple regression analysis that the results are greatly different if the content is changed even for the same composition element.

Incidentally, although the values of the multiple correlation coefficient R and the determination coefficient R2 are good, the degree of freedom corrected determination coefficient R2 (correction R2) and the value of the significant F are bad. The correlation is not sufficiently obtained, and the trial listening evaluation value Y is only “4.33” at the maximum value. Therefore, it cannot be said that it is an optimal acoustic solder alloy.

Incidentally, audio solder alloy having the same composition elements, because they are used as 12 joining solder of the filter circuit _NW _(NW0 1 ~ NW0 ₁₂₎ for the filter circuit NW0 ₁ are shown in "this Example 1" contained audio solder alloy amount is used, the filter circuit NW0 ₂ is audio solder alloy content shown in "present embodiment 2" is used. Similarly, in the filter circuits NW0 ₃ to NW0 ₁₂ , the sound quality and the audition are evaluated using the acoustic solder alloys shown as data 1 to data 10 (see Table 1).

(9) Audition evaluation with acoustic solder alloys in other groups None of the following acoustic solder alloys of groups 2 to 5 were able to obtain the audition evaluation as in “Example 1” or “Example 2”. Indicates data. The results are shown below.

(2) Group 2 acoustic solder alloy This group of acoustic solder alloy compositions uses Pb and Sb as a common additive metal, as shown in (Table 1). Alloy: (Sn / Ag / Cu / Sb / Pb) with one kind added from (Bi / Fe / As / In / Ni). Therefore, there are five types of acoustic solder alloys.

The correspondence tables showing the results of the multiple regression analysis when using this acoustic solder alloy are (Tables 9 to 23).
(1) (Tables 9 to 11): Results of analysis of an acoustic solder alloy comprising (Sn, Ag, Cu, Sb, Bi, Pb) (2) (Tables 12 to 14): (Sn, Ag, Cu) (3) (Table 15 to Table 17): Analysis result of acoustic solder alloy made of (Sn, Ag, Cu, Sb, As, Pb) (Sb, Fe, Pb) 4) (Tables 18 to 20): Analysis results of an acoustic solder alloy made of (Sn · Ag · Cu · Sb · In · Pb) (5) (Tables 21 to 23): (Sn · Ag · Cu · Analysis results of acoustic solder alloys made of Sb / Ni / Pb)

(A) (Tables 9 to 11): Analytical results of an acoustic solder alloy composed of (Sn, Ag, Cu, Sb, Bi, Pb) are shown below.

As is clear from (Table 9) to (Table 11), it is difficult to say that this is the optimal acoustic solder alloy.

(B) (Tables 12 to 14): The analysis results of the acoustic solder alloy comprising (Sn, Ag, Cu, Sb, Fe, Pb) are shown below.

As is clear from (Table 12) to (Table 14), it is difficult to say that it is an optimal acoustic solder alloy.
(C) (Tables 15 to 17): The analysis results of the acoustic solder alloy comprising (Sn · Ag · Cu · Sb · As · Pb) are shown below.

As is clear from (Table 15) to (Table 17), it is difficult to say that it is an optimal acoustic solder alloy.
(D) (Table 18 to Table 20): The analysis results of the acoustic solder alloy composed of (Sn · Ag · Cu · Sb · In · Pb) are shown below.

As is clear from (Table 18) to (Table 20), it is difficult to say that this is an optimal acoustic solder alloy.
(E) (Tables 21 to 23): Analytical results of the acoustic solder alloy made of (Sn, Ag, Cu, Sb, Ni, Pb) are shown below.

As is clear from (Table 21) to (Table 23), it is difficult to say that this is an optimal acoustic solder alloy.

(3) Audition evaluation of acoustic solder alloy of group 3 The composition of acoustic solder alloy of this group is such that Pb and Bi are added to (Sn · Ag · Cu) as a common additive metal. Acoustic solder alloy: (Sn / Ag / Cu / Bi / Pb) added with one kind from (Fe / As / In / Ni). Therefore, there are four types of acoustic solder alloys.

The correspondence tables showing the results of multiple regression analysis when using this acoustic solder alloy are (Tables 24 to 35).
(1) (Tables 24 to 26): Analysis results of an acoustic solder alloy made of (Sn / Ag / Cu / Bi / Fe / Pb) (2) (Tables 27 to 29): (Sn / Ag / Cu) (3) (Tables 30 to 32): Analysis results of acoustic solder alloy consisting of (Sn, Ag, Cu, Bi, In, Pb) (Bi, As, Pb) 4) (Table 33 to Table 35): Analytical results of acoustic solder alloy composed of (Sn, Ag, Cu, Bi, Ni, Pb) (a) (Table 24 to Table 26): (Sn, Ag, Cu, The analysis results of the acoustic solder alloy made of (Bi · Fe · Pb) are shown below.

As is clear from (Table 24) to (Table 26), it is difficult to say that it is an optimal acoustic solder alloy.
(B) (Tables 27 to 29): Analytical results of the acoustic solder alloy consisting of (Sn, Ag, Cu, Bi, As, Pb) are shown below.

As is clear from (Table 27) to (Table 29), it is difficult to say that this is an optimal acoustic solder alloy.
(C) (Tables 30 to 32): The analysis results of the acoustic solder alloy comprising (Sn · Ag · Cu · Bi · In · Pb) are shown below.

As is clear from (Table 30) to (Table 32), it is difficult to say that this is an optimal acoustic solder alloy.
(D) (Table 33 to Table 35): Analytical results of the acoustic solder alloy composed of (Sn, Ag, Cu, Bi, Ni, Pb) are shown below.

As is clear from (Table 33) to (Table 35), it is difficult to say that this is the optimal acoustic solder alloy.

(4) Audition evaluation of acoustic solder alloy of group 4 The composition of acoustic solder alloy of this group is such that Pb and Fe are added to (Sn · Ag · Cu) as a common additive metal. Acoustic solder alloy: (Sn / Ag / Cu / Fe / Pb) added with one type from (As / In / Ni). Therefore, there are three types of acoustic solder alloys.

The correspondence tables showing the results of multiple regression analysis when using this acoustic solder alloy are (Table 36 to Table 44).
(1) (Tables 36 to 38): Analysis results of an acoustic solder alloy comprising (Sn · Ag · Cu · Fe · As · Pb) (2) (Tables 39 to 41): (Sn · Ag · Cu) (3) (Tables 42 to 44) Analysis result of an acoustic solder alloy made of (Sn, Ag, Cu, Fe, Ni, Pb) (Fe, In, Pb) a) (Table 36 to Table 38): The analysis results of the acoustic solder alloy comprising (Sn · Ag · Cu · Fe · As · Pb) are shown below.

As is clear from (Table 36) to (Table 38), it is difficult to say that it is an optimal acoustic solder alloy.
(B) (Table 39 to Table 41): Analytical results of an acoustic solder alloy composed of (Sn · Ag · Cu · Fe · In · Pb) are shown below.

As is clear from (Table 39) to (Table 41), it is difficult to say that it is an optimal acoustic solder alloy.
(C) (Tables 42 to 44): Analytical results of an acoustic solder alloy composed of (Sn, Ag, Cu, Fe, Ni, Pb) are shown below.

As is clear from (Table 42) to (Table 44), it is difficult to say that it is an optimal acoustic solder alloy.

(5) Audition evaluation of acoustic solder alloys of group 5 The composition of acoustic solder alloys of this group is such that Pb and As are added to (Sn · Ag · Cu) as a common additive metal. Solder alloy for acoustic: (Sn / Ag / Cu / As / Pb) added with one kind from (In / Ni). Accordingly, there are two types of acoustic solder alloys.

The correspondence tables showing the results of multiple regression analysis when using this acoustic solder alloy are (Tables 45 to 50).
(1) (Table 45 to Table 47): Analytical results of acoustic solder alloy comprising (Sn · Ag · Cu · As · In · Pb) (2) (Table 48 to Table 50): (Sn · Ag · Cu (A) (Table 45 to Table 47): Analysis result of an acoustic solder alloy consisting of (Sn, Ag, Cu, As, In, Pb) It is shown below.

As is clear from (Table 45) to (Table 47), it is difficult to say that this is an optimal acoustic solder alloy.
(B) (Table 48 to Table 50): The analysis results of the acoustic solder alloy comprising (Sn · Ag · Cu · As · Ni · Pb) are shown below.

As is clear from (Table 48) to (Table 50), it is difficult to say that it is an optimal acoustic solder alloy.

In the above-mentioned groups 2 to 5, any two kinds of metals except (In, Ni) are added to (Sn · Ag · Cu · Sb · Pb) except for (Bi · Fe · As · In · Ni). The sound quality and audition evaluation of the obtained acoustic solder alloy are as follows. As shown in (Table 9) to (Table 50), all of the 6-component acoustic solder alloys comprising these combinations have excellent sound quality characteristics. Also, a high audition evaluation value could not be obtained.

As described above, according to the present invention, discrete components are soldered onto a printed circuit board (circuit board), so that the bonding solder used in a filter circuit or the like that constitutes an electronic circuit can be used as shown in Group 1. The original solder alloy (Sn / Ag / Cu / Sb / In / Ni / Pb) and a solder alloy for sound that has high sound quality and high audition evaluation with an appropriate content have been developed.

1 is an example, and a three-way type audition evaluation device can also be used for audition evaluation.

As the acoustic solder alloy, solder containing solder was used, but it is not limited to this, and it may be a solder ball, a solder paste, or the like, and its form and shape are not limited. Moreover, also in the soldering method, you may use methods, such as a reflow furnace and a jet solder bath. Furthermore, although the description has been made using the discrete component as the electronic component, a chip-shaped electronic component may be used.

Further, in the above-described example, the filter is applied to the filter circuit as solder for joining the electronic components, but the acoustic solder alloy according to the present invention can be applied as the solder for connecting the electronic components constituting the entire audio system. By doing so, further improvement in sound quality can be expected.

The acoustic solder alloy according to the present invention can be applied to bonding solder used for soldering various electronic components used in an audio system onto a printed circuit board (circuit board).

DESCRIPTION OF SYMBOLS 10 ... Audition evaluation apparatus 20 ... Sound source 30 ... Output amplifier NW0-NW15 ... Filter circuit 40 ... Low pass filter 50 ... High pass filter WF, TW ... Speaker

Claims

Ag is 0.8 to 1.20 mass%, Cu is 0.65 to 0.75 mass%, In is 0.002 to 0.004 mass%, Ni is 0.01 to 0.02 mass%, and Pb is An acoustic solder alloy comprising 0.005% by mass or less and the balance being composed of Sn.
Ag is (1.0 to 1.01% by mass), Cu is (0.71 to 0.72% by mass), In is (0.003 to 0.0037% by mass), and Ni is (0.016 to 0%). The solder alloy for sound according to claim 1, wherein Pb is (0.0025 to 0.0035% by mass) and the balance is Sn.